Circuit-breaker.



J. E. EVANS.

CIRCUIT BREAKER.

APPLICATION FILED SEPT.27, 1911.

Patented Feb. 4, 1919.

FIG].

la r Fla INPINTOR UNITED STATES PATENT OFFICE.

JAMES E. EVANS, OF ARTESIA, CALIFORNIA, ASSIGNOR 0F ONE-HALF T0 FRANK FOSTER, 0F ARTESIA, CALIFORNIA.

CIRCUIT-BREAKER.

Specification of Letters Patent.

Patented Feb. 4, 1919.

Application filed September 27, 1917. Serial No. 193,483.

heating circuits in incubators.

The principal object of this invention isto provide an automatically operating ther mostat control by which the electric circuit of heating elements may be instantly broken and closed at predetermined temperatures.

Another object of this invention is to provide a device of the above character with simple adjustment whereby the thermostat will positively operate within a given range of temperature.

Other objects will appear hereinafter.

' The invention is illustrated, by way of example, in the accompanying drawings in which:

Figure 1 is a view in side elevation illustrating the preferred form of the invention as disassociated from its intended mounting.

Fig. 2 is'a view in plan illustrating the form of the device shown in Fig. 1 and further indicating an electric circuit controlled thereby.

Fig. 3 is a fragmentary view in end elevation illustrating the contacts of the device shown in Fig. 1.

Fig. at is a fragmentary view in vertical section illustrating the thermostat by which the mechanism is operated.

Fig. 5 is a view in side elevation illustrating a modified form of the invention.

Fig. 6 is a view in plan illustrating the form of the invention shown in Fig. 5.

Referring particularly to Figs. 1-4 inclusive, 10 indicates a base upon which a per ends which engage a cross bar at the end of the lever. The opposite end of the lever is shorter and wider so that the weight of the lever upon opposite sides of its pivotal mounting will be substantially counterbalanced. Secured to the forward end of the balanced lever. and insulated therefrom 1s a resilient blade 17 having a V-shaped contact point 18 at its lower end. This point is adapted to be brought to bear against the curved faces of contact members 19 and 20 secured tothe base and insulated from each other, where it will properly seat due to its yieldable mounting. An electric conductor 21 is connected with the member 19 and a second conductor 22 is fastened to the member 20.

A central vertical standard 23 is fastened to the baseat a point between the position of the contact members and the standards 11 and 12. This last-named standard extends upwardly through a large rectangular opening 24 in the balanced lever and .provides pivotal support for a tension lever 25. The lever 25 is formed with a downwardly extending end terminating slightly ahead of the pivotal center of the balanced lever and to which a tension spring 26 is secured. The opposite end of this spring is fastened to the rear end of the balanced lever and'extends along the center of the rectangular opening therein. The tension lever, has a short forked arm 27 at its opposite end between the prongs of which a double collared adj ustment nut 28 is disposed. The collars are spaced from each other to permit the apparatus to have considerable movement without strain upon the parts.

The adjustment nut is mounted upon the upper threaded end of a thermostat rod 29 which extends downwardly through the base and is secured to the upper plate of an expansive thermostat 30. The thermostat rod extends through a guide tube 31 fixed through the base 10. A trip nut 32 is also mounted upon the threaded end of the rod 29 and has diametrically oppositely extending Wings 33 and-34 which normally are positioned laterally of the balancing lever and may be raised to engage the side portions thereof. Normally one wing of the nut is disposed to bear downwardly upon the horizontal leg 35 of a catch bell crank 36, the opposite leg of which extends vertically and is formed with a catch recess 37 I which maybe brought to register with a 'when the pressure of lug 38 forming a part of the balanced lever,

the nut 32 is relieve therefrom.

The wings 33 and 34 extend from the nut 32 crosswise of the lever 14 and under the ends of the lever so that when the rod 29 is raised by the thermostat the wings will engage the lever 14 and raise the lever and at the same time the bell crank 36 will be raised by the tension of the spring-to swing the vertical leg of the bell crank against the lug 38 and when the lever has been raised far enough the lug 38 will pass into the notch 37 and latch the lever 14 in its upper position, and this end of the lever 14 will stay in its upper position until the thermostat contracts and the wing 34 moves downwardly to swing the arm 35 downwardly to bring the ln 38 out of the notch 37 ,and then the end or the lever will swing downwardly. I

In the modified form of the invention shown in Fig. 5, a base 39is provided upon which a balanced lever 40 is mounted. This lever is mounted between uprights 41 similar to the uprights 11 and 12 in the device previously described. The outer end of the balanced lever is formed with a contact member 42 normallybearing against a similar member 43 secured upon a supporting bracket- 44 which extends upwardly in the rectangular opening of the balanced lever. In this casethe balanced lever is U-shaped, the open end of the lever being closed by a strip of insulating material 45 to which one end of a tension spring 46 is fastened. The

"opposite end of this spring is fastened to the downwardly extending end of a tension lever 47' which extend-s rearwardly and is mounted upon a pivot pin 48' positioned within a bracket 49 upon the base. A thermostat rod 50 passesthrough an opening in the end of the lever 47 and is therelitted with an adjusting nut51. The thermostat rod extends downwardly through a guide tube and enga es the end of a thermostat lever 52 which 1s borne against by a thermostat 53. The lever and thermostat are secured upon a bracket 54 mounted at the lower end of the guide tube.

The two devices described above are provided to control an electric circuit consisting of the two conduits 21 and 22, a source of electric supply 55, and an electric heating element 56. In the oneinstance, the circuit is completed by forming a contact across the contact members 19. and 20 by the movable member 18, while with the other device the circuit is completed by forming a contact from one upright 41 through the balanced lever 40 thence through the contact members 42 and 43 and to the conduit 22 along the bracket 44.

In the operation of the form of the device reeasee shown in Figs. 1-4 it will be assumed that the contact members 19 and 20 are electrically connected due to the fact that the'contact 18 is wedged between them. This com pletes the circuit through the heating element as previously described. circuit is thus completed the heating element will be in operation and will be so disposed as to effect the thermostat. As the temperature of the air surrounding the thermostat is raised, the thermostat will expand and the thermostat rod will be moved upwardly, the lower collar of the nut 28 bearing against the forked end of the tension lever to swing the opposite end of the lever downwardly asindicated by the arrow -ain Fig. 1. This movement will exert a tension upon the spring 26 and when the lever has passed sufliciently below the center of balance of the balanced lever 14 will act to swing the contact end of the balanced lever upwardly in the direction of the arrow b--- in Fig. 1. At the time this action takes place, the trip nut 32 will be raised from engagement with the leg of bell crank 36 and will permit its spring 36 to swing it in the direction of the arrow -c and cause the lug 38 upon the balanced lever to seat within the notch 37 upon the bell crank. This will positively support the contact member 18 until after the trip nut again strikes the leg of the crank as the thermo- When the stat is contracted, after which time the receding movement of the tension lever Wlll act to swin the balanced lever downwardly and restabish communication between the contacts 19 and 20. Due to this arrange ment it is possible to make and break a circuit even though the movement of the initial'actuating mechanism is slow. In case the tension spring is broken, the wings upon the trip nut will lift'the balanced lever as the thermostat expands, thus making the device proof against accident.

In the modified form of the invention the operation is similar. In this case the expansion of the thermostat is downwardly and acts to swing the thermostat lever 52 in the direction of the arrow d as shown in Fig. 5. This pulls downwardly upon the thermostat rod and causes an upward swinging movement of the tension lever 47 in the direction of the arrow e-. This movement is effected against the adjustable coun-' terweight 57 and the tension of the spring 46. As the tension lever swings upwardly, the point from which force is applied to the llli - lever will be transferred above the center of a will operate positively and effectively to lnstantly make and break an electric current when the force controlling the device is slowly acting. I

While I have shown the preferred construction of my circuit breaker as now known to me, it will be understood that various changes in the combination, construction, and arrangement of parts may be made by thoseskilled in the art without departing from the spirit of my invention as claimed.

.I claim: 1. A circuit breaker comprising a slowly expanding thermostat element, a lever actuated by said element, a second lever upon which a contact member is mounted, means whereby a slow movement of the first named lever by the thermostat will cause an instant movement of the second-named lever at a moment during the expansive action of the thermostat, means for adjusting the mechanism to predetermine the moments of instant actuation of the secondnamed lever, means for instantly restoring the second-named lever to its originalposition at a given momentduring the contraction of the thermostat, means for positively locking the'second-named lever in its uppermost position after actuation upon the expansive stroke of the thermostat, and

posltively acting-adjustable means for releasing said secondmamed lever from the locking means at a point in the contracting stroke of the thermostat.

2. A circuit breaker comprising a base, a thermostatic element mounted beneath said base, through the base from the element, an adjustable double-collared nut mounted upon the upper threaded end of. said rod, a ten sion lever pivotally mounted above the base and having a bifurcated end, the prongs of which extend along opposite sides of the double-collared nut and between the collars thereof, a. tension spring secured at the opposite end of said lever, a balanced lever pivotally mounted upon the base and to one end of which the oppositeend of the tension spring is secured, a resilient blade secured to the oppositeendof the balanced lever and extending downwardly therefrom, a contact point fastenedupon the lower end of said blade, a pair of spaced contact members dielectrically mounted'upon the base and between which the point may be engaged, and means whereby a slow movement of the tension lever will at a given moment transfer the tension of the spring to opposite sides of the center of balance of the balanced lever as the thermostat contracts and expands and instantlymake and break cona thermostat rod extending upwardly tact between the contact point and the contact members.

31A circuit breaker comprising a base, a thermostatic element mounted beneath said base, a thermostat rod extending upwardly through the base from the element, an adjustable double-collared nut mounted upon the upper threaded end of, said rod, a tension lever pivotally mounted above the base and having a bifurcated end, the prongs of which extend along opposite sides of the double-collared nut and between the collars thereof, atension spring secured at the opposite end of said lever, a balanced lever pivotally mounted upon the base and to one end of which the opposite end of the tension spring is secured, a resilient blade secured to the opposite end of the balanced lever and extending downwardly therefrom, a contact point fastened upon the lower end of said blade, a pair of spaced contact members dielectrically mounted upon the base and between which the point may be wedged,

means whereby a slow movement of the tenthe balanced lever in its uppermost position and releaseit therefrom, and means whereby the trip-nut may actuate the mechanism in the event of the breakage of parts thereof.

4. In a circuit breaker, a balanced lever pivotally mounted in a horizontal plane, a tension lever pivotally mounted. above the balanced lever, a spring connecting one end of the tension lever to one end of the ba-lanced lever, said spring being normally substantially parallel with the balanced lever and the endof the spring which is connected to the tension lever being adapted to swing up and down past the plane of the balanced lever, and a thermostat for operating the tension lever.

a trip-nut mounted upon the 5. In a circuit breaker, a bifurcated balnecting the tension lever tothe balanced.

lever, said spring being located in the opening between the bifurcations, and therm0- static means for operating the tension lever. In testimony whereof I have signed my name to this specification.

' JAMES E. EVANS. 

